In recent years there has developed increased interest in replacing or augmenting sutures with adhesive bonds. The reasons for this increased interest include: (1) the potential speed with which repair might be accomplished; (2) the ability of a bonding substance to effect complete closure, thus preventing seepage of fluids; and (3) the possibility of forming a bond without excessive deformation of tissue.
Studies in this area, however, have revealed that in order for surgical adhesives to be accepted by surgeons, they should possess various properties. For example, they should exhibit high initial tack and an ability to bond rapidly to living tissue; the strength of the bond should be sufficiently high to cause tissue failure before bond failure; the adhesive should form a bridge, typically a permeable flexible bridge; and the adhesive bridge and/or its metabolic products should not cause local histotoxic or carcinogenic effects.
Several materials useful as tissue adhesives or tissue sealants are currently available. One type of adhesive that is currently available is a cyanoacrylate adhesive. However, there is the possibility that a cyanoacrylate adhesive can degrade to generate undesirable by-products such as formaldehyde. Another disadvantage with cyanoacrylate adhesives is that they can have a high flexural modulus which can limit their usefulness.
Another type of tissue sealant that is currently available utilizes components derived from bovine and/or human sources. For example, fibrin sealants are available. However, as with any natural material, variability in the material is frequently observed and, because the sealant is derived from natural proteins, there may be viral transmission concerns.
It would be desirable to provide a biological adhesive or sealant that is fully synthetic and therefore highly consistent in its properties without the concern of viral transmission. Such a composition should be flexible and biocompatible and should be suitable for use as an adhesive or sealant.